The present invention relates to a novel catalyst for the polymerization of olefins.
Heretofore, in the technical field of this sort there have been known various catalysts comprising inorganic magnesium solids as carriers such as magnesium halides, magnesium oxide and magnesium hydroxide, and transition metal compounds supported thereon such as titanium compounds and vanadium compounds. However, if olefins are polymerized using these known catalysts, the bulk density of the resulting polymer is generally low, the average particle size is relatively small and the particle size distribution is generally wide, allowing a particulate portion to occupy a fairly large portion, thus causing a serious drawback in the aspects of productivity and handling. Moreover, when molding the resulting polymer, there arise problems such as the generation of dust and the decrease of efficiency in the molding operation. Therefore, it has been a keen desire to increase the bulk density and to decrease a fine particulate portion. Furthermore, for the application to a processing method wherein a pelletizing step is omitted and a powdered polymer is directly fed to a processing machine, a demand for which has recently been increasing, it is considered that further improvements are necessary.
It is an object of the present invention to remedy the above-mentioned drawbacks.
It is another object of the present invention to provide a novel polymerization catalyst which can afford olefin polymers having a high bulk density, a large average particle size, a narrow particle size distribution and a remarkably small proportion of a fine particulate portion.
Other objects and advantages of the present invention will become apparent from the following description.